Improvement in millstone-drivers



2 Sheets-Sheet 1.

W. JOHNSON. Millstone-Driver.

No. 222,50l. Patented Dec. 9,1879.

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2 Sheets-Sheet 2.

W. JOHNSON. Millstone-Driver.

Patented Dec. 9, 1879.

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WILLIAM JOHNSON, OF MILWAUKEE, WISCONSIN, ASSIGNOR TO HIMSELF AND GEORGE W. MARLING, OF SAME PLACE.

IMPROVEM ENT IN MILLSTONE-DRIVERS.

Specification forming part of Letters Patent No. 222,501, dated December 9, 1879; application filed February 6, 1879.

To all whom it may concern:

Be it known that I, WILLIAM JOHNSON, of Milwaukee, in the county of Milwaukee and State of Wisconsin, have invented'certain new and useful Improvements in Millstone-Drivers; and I do hereby declare the following to be a full, clear, and exact description thereof, reference being had to the accompanying drawings and to the letters of reference marked thereon.

The nature of my invention consists in the construction and arrangement of a millstonedriver which shall drive the stone uniformly and steadily, and shall correct the irregularities arising from any imperfect tram of the spindle, and at the same time be durable and not liable to get out of order.

In order to enable others skilled in the art to which my invention appcrtains to make and use the same, I will now proceed to describe its construction and operation, referring to the annexed drawings, which form a part of this specification.

Figure l is a perspective view of my improved millstone-driver. Fig. 2 is a side view,

and Fig. 3 a central vertical section, of the same. Fig. 4 is a bottom view of the driving bar or yoke. Fig. 5 is a plan view of the bed. Fig. 6 is a detached section of a part thereof, showing the supplemental jaw.

A represents the bed-plate, formed with a central bushing, F, whichextends upward for a suitable distance, and has lugs projecting therefrom to enter correspondingly shaped recesses in the cap-plate 0, said cap -plate being attached firmly by means of screws '5 i. Between the bed A and cap 0, which are formed substantially in the shape shown, slides the yoke or driver B,in a direction at right angles to the spindle, and parallel with a horizontal line drawn in the perpendicular plane which passes through the middle of both extremities of the bail.

The bed-plate Ais provided with four hardened steelfriction-rollers, 9, upon which the driver B rests, and also with two upwardlyprojecting guide blocks, (1, which are faced with bearers c, of box-wood or equivalent material.

The bushing F of the bed-plate passes upward through a large orifice in the center of the driver B, and the mill-spindle is to be accurately fitted in said bushing.

The driver B is, on its under surface, provided with thin polished steel bearing-plates E, which rest upon the rollers g, and it has also two recesses, a, which are provided with polished brass faeings c, the said recesses fitting over the bearers d, the two forming guides for the driver B.

D D represent supplemental jaws having flat bearing-surfaces, which engage with the face of the millstone-bail, and are preferably formed of brass or equivalent materiah Each jaw is formed with a nearly-cylindrical shank, D, extending vertically in the center of the back and joined by a short neck to the jaw, as shown in Fig. 4. The edges of the jaws formed on the driver B are drilled for the reception of the shank D, and a slot made out through the face wherein the neck joining the jaw D and its shank plays.

The hole mentioned is not drilled entirely through, but only deep enough to receive a rubber block, as, then the shank D, and then another rubber block, y, after which the aperture is closed by a short screw, z. This is fully illustrated in Fig. 6.

On the top of the driver B are bearers K of lignum -vitae, box-wood, or other suitable material, which bear and slide against the lower surface of the top plate 0. The driver B is recessed, as shown at l, for the reception of the top plate, 0, which is then flush with the jaws of the driver, and additional hearings or guides are thus formed for the driver B, which greatly conduces to the strength and freedom of action of the same.

The supplemental jaws D are hinged, as described, to the jaws of the driver, and have both a pivotal motion laterally on their rounded shanks, and a slight elastic motion in a perpendicular line, owing to the elasticity of the rubber blocks :0 y. The first motion allows them to accommodate themselves to the face of the bail. The latter motion permits them to yield to the trembling of the stone, and by the elasticity of the rubber correct the inequalities of motion therein.

Having thus fully described my invention,

3. The combination of the driver B, the jaws D, having round shanks D, and the rubber blocks w y, substantially as and for the purposes herein set forth.

In testimony that I claim the foregoing as my own I aflix my signature in presence of two witnesses.

WM. JOHNSON. Witnesses:

S. G. LAPHAM, E. H. 130mm. 

